Feed control for pulverizing mills



Nov. 3,1925. 1,559,786

O. A. SAUER FEED CONTROL FOR PULVERIZING MILLS Filed Aug. 16. 1923 2'Sheets-Shut L Nov. 3, 1925. 1,559,786

O` A. SAUER FEED CONTROL FOR PULVERIZING MILLS Filed Aug. 16, 1923 2Sheets-Shut 2 Y ,YZ/nde fab/Oft Patented Nov. 3, 1925.

UNITED STATES PATENT oFElcE.

OTTO A. SAUER, OF SAN ANTONIO, TEXS, ASSIGNOR THREE-FOURTHS TO EUGENE D.NIMS, OF ST. LOUIS, MISSOURI.

FEED OONTROL FOR .PUL'VERIZING MILLS. l

Application filed 'August 16, 1923. Serial No. 657,796.

To all lwhom t may concern.'

Be it known that I, OTTO A. SAUER, a citizen of the United States ofAmerica, and a resident of San Antonio, county of Bexar, and State ofTexas, have invented a new and useful Improvement in Feed Control forPulverizing Mills, of which the following is a specification. i

This invention relates to feed control means for roller-mills whereinthe pulverized product is removed'from the mill by an air current.

The main objects of this inventionJ are to provide improved mechanismfor controlling the feeding of raw material to the mill; to provideimproved mea-ns actuated by the condition of the air current forregulating said feeding mechanism; and to provide improved related meansand mechanism of this kind whereby the feeding of raw material isautomatically proportioned to the -capacity of the mill to elfect asatisfactory pulverization and removal ,of the material.

An illustrative embodiment of this in- I vention is shown in theaccompanying drawings, in which:

Figure v1 is a vertical, sectional elevation of a special typeofpulverizing roller-mill showing an improved v feed control, constructedin accordance with this invention, applied thereto, the feed controlbeing illustrated somewhat diagrammatically.

Figure 2 is a plan of the same.

Figure 3 is a detail view Afurther illustra-ting the manner in whiclrthefeed control functions. f t

One common form of pulverizing mill heretofore in use requires theconstant services of an attendant to control the feedof material intothemill so as to prevent choking at the crushing rollers. The presentinvention provides a roller mill which is entirely automatic in itsoperation so as lnot to require thev services of an attendant after thematerial has been placed in the hopper to be fed to the rolls. Thedevice includes improved automatic mechanism for controlling the feed ofmaterial from the hopper to the rolls. This improved mechanism isactuated by an air motor controlled by changes in the static pressure ofthe air current within the mill, depending upon the amount of materiallocated at the rolls. In construction, the mill is somewhat similar to aVen- `turi tube in which thev grindingv chamber forms the reducing coneand the separating chamber forms the expanding cone, with the rollerslocated at the throat of the Venturi tube. The material in process tendsto obstruct the passage of the air through the throat, therebycontrolling the static pressure in the grinding chamber. static pressurein the grinding chamber is proportional lto the amount of materialobstructing the throat.` If the mill is choked by an excess amount ofmaterial, the air pressure in the grinding chamber increases and the airmotor is thereby actuated to close the inlet valvel of the feed chuteuntil a sufficient amount of material passes through the rolls tomaterially reduce the air pressure within the grinding chamber.

In Athe specific4 embodiment herein illustrated,the improved feedcontrol is shown asappliedto avertical pulverizing mill of The.v

the Raymond type, but it is also applicable to other types and makes ofmills.

The mill comprises a housing 1 which pro-4 l vides-a grinding chamber 2andan air'separating chamber 3 arranged' one above the other andcommunicating with each other.

The raw material enters through the openl ing 4 where'itis delivered tothe grinder 5 and the pulverized linished product isv carried-by an aircurrent up intothe separator able collector c. An air inlet pipe 7connects with an annular conduit v7A surrounding the grinding chamber 2and communicating with said conduit through ports 7b for distributingthe incoming air in the grinding 3 and out through an outlet port6 to asuitsusl This pendulous mounting of the rollers 8 causes them to swingoutwardly during the rotation of the member 11 sol as to bear` against abull-ring 14 arranged on the adjacent inner wall of the housing 1.Rigidly mounted on the carriage 11 is a plurality of blades or plows 15located in advance of each roller 8 and arranged to revolve with thecarriage 11 and to lift the raw material in the grinding chamber to alplane .where it is caught between the rollers 8 and bullring 14. l

Suitable air 'pumping mea-ns such as a blower B connects with the airinlet pipe 7 pulley 35 is arranged on shaft 32 for conso as to set up anair current through the nection with a source of power.

grinding and separating chambers for the The mill, and the feed .controltherefor, purpose of forcing the pulverized product' as herein shown anddescribed operate Subjl through the grinder 5 and discharging itstantiallyv in the following mannen' .e

into the collector C from which collector As the carriage 11 isrotated-the rollers the finished product is delivered to suitable swingout against and revolve around t e containers. It -is desirable Atoconnect. the bull-ring 14. The vplows 15 throw the ma\ airoutlet of thecollector to the blower B terial up between-the rollers 8 andthe bullilso that any of the dust escaping from the' ring 14 where 1t ispulverized by the grind- 75" collector is carried back to the mill anding action of the rollers and bull-ring. The

again delivered to the collector. air current produced by the blower Bforces rlv`he specific embodiment of the feed con# such of the finematerial as is not too heavy trol herein shown comprises a chute 16\plpinto the separating chamber 3 and out through which a iow of material isconough the port 6 and delivers it to the trolled by a pair of gates 17and 18 opercollector C. The materialthat is too heavy ated respectivelyby an eccentric and crank to be removed by the air current falls backmechanism 19 and a motor device 20. in the grinding chamber 2 and isre-ground.

rIhe chute 16 is suitably arranged withlv vAs the mill operates theeccentric 21, actrespect to the mill and has its lower end coningthrough the rod 23 and arm 24, shaft -25 'nected to the material inlet 4and its upper and arm 26, reciprocates the gate 17 causend connected toa bin or other suitable ing it to be intermittently opened and closedAbove that the chute may be partially open arranged for that purpose.The gate 18 is terial to pass to the material opening 4. If.

source of supply. Inasmuch as there is an for releasing and checking theflow ofraw air current throughthe mill thechute is material through vthechute 16 toward the substantially air tight up to the gate 18. gate 18.y

j -The gate 18 is normally arranged so as to on the top side if desir d.be raised from the bottom of the chute a The gate 17 is slidably mountedtrans-v predetermined distance such as will allow versely of the chuteinsuitable guideways for a predetermined quantity of raw masimilarlyvmounted in the chute between for an reason an excessive amount of thethe gate 17 and the material inlet 4 of the pulverized material in thegrinder 5 and in mill. the Separating chamber -3 tends to retard Theeccentric and crank mechanism 19 the free movement of the air currentand dust for operating the gate 17 includes an eccentherethrough, thereis a building up of tric 21 journaled on a shaft-22 and having Ypressure in the grin'dingchamber 2 and inl a rod 23 connecting it withan arm 24l which the annular conduit 7A. This increased bellows ofdiaphragm construction arranged mill.

is attached to a shaft 25 journaled on chute pressure reacts on thediaphragm motor de- 16 and connected to the gate 17 by an arm vice 20 soa's to cause it to shift the gate 18 26. The connection of the rod 23and arm to reduce the size of the opening between 24 is made adjustableso. as to vary the aeit and the chute, thus decreasing the supply tionof the eccentric-crank mechanism 19 0f raw material fed t0 the mill. AS4S0011 on the gate. During the operation of the as the accumulation ofpulverized material mill, the gate 17 is reciprocated continuously inthe mill is eliminated and a normal flow so as to serve as an agitatorthereby faeiliof air current is re-'established the diatating the flowof material through the phragm motor 20 reacts so as to produce a chute.j further opening of the gate 18 and an in- The motor device 2O is asuitable form of crease of the supply l0f MW material t0 the on the sideof the housing 1 adjacent to the It will thus be seen that through theme- 'grinding chamber 2 se as t0 communicate dium of the motor device 20and its ine- I with the annular air conduit 7^. A `rod 27 ChalllcalConnections t0* the gate-18 the sul" and a rod 28, connected together bya bellply 0f IaW .material iS automatically PrO- crank lever 29,communicate the movements portoned t0 the capacity of the mill to ul- 0fthe diaphragm motor device 20 te the verize the same and have thepulverized gate 18 through the medium 0f a, lever 30 product removed bythe air current. Such mounted on the chute 16. A turnbuekle 31 a feedcontrol .results in a more steady and maybe arranged on rod 28 for thepurpose uniform operation of a mill and a more a suitable belt andpulley connection 34. 'A altered o1, omitted without'dep-arting from ofproperl adjusting .the gate 18 to the -uniform andabundant yield of thefinished action of t e motor device 20. product.

The driving mechanism for themill and Although but one specificembodiment of -the feed control comprises a driving shaft this inventionhas been herein shown and 32 which.4 is connected to; the shaft 12 bydescribed, it will be understood that certain gear and pinion 33 and tothe sha-ft 22 by details of the .construction shown may be the spirit'of this invention as Idefined by the following claims.

I claim: p

l. In a pulverizing machine, grinding means, a feed control, comprisinga chute, a pair of gates arranged to control the flow of material alongsaid chute, mechanism connected to be actuated by the means forconstantly reciprocating one of said gates 4for intermittently checkingand releasing the flow of material along said chute, a motor Vdeviceconnected with the machine and adapted to be actuated by changes createdtherein by variations in the vo-lume of the finished product, and amechanical connection between said motor `device and the other gate,whereby said other gate is shifted by said motor device for regulatingthe quantity of material delivered to the of material along said chute,vand a diaphragm motor device connected with said machine and adapted tobe actuated by changes in the air current created by variations in thevolume of finished product, said motor device being connected to theother gate, whereby said other gate is shifted by said motor device forregulating the quantity of material delivered to the machine.

3. A pulverizing mill comprising a grinding chamber, an air separatingchamber above said grinding chamber and communieating therewith througha restricted throat, grinding means located in said throat, aircirculating means for normally forcing a current of air upwardly throughsaid chambers, means controlling the feed of material to said chambers,and an air motor communicating with said Grinding chamber below saidthroat and a apted to be actua-ted by an increase of air pressure insaid grinding chamber through the choking of said throat by an excessamount of material, said air motor being arranged to actuate said feedcontrol means for reducing the feed of material when said throat ischoked.

Signed at San Anto-n10 this 9th day of August, 1923.

. OTTO A. SAUER.

